How much is a kWh?

Hello Readers,

As I was writing my series on Net Metering, it was pointed out to me that most people are not especially familiar with some of the units that I used in the article. Thus, in this post, I would like to offer a primer on units that are commonly used when talking about electricity (and how they relate to renewable energy and energy use). At the bottom of this post, I have also included a glossary of Energy Industry Terminology that you may encounter while reading about renewable energy and energy use.

What's a Watt?

A Watt (W) is a basic unit of power measurement. Watts are used to measure how quickly energy is consumed by or generated by a system.

But what about all of the prefixes?

Unit Name	Abbr.	Meaning	At This Scale
Microwatts	μW	1/1,000,000th Watts	Wrist Watches
Milliwatts	mW	1/1,000th Watts	Laser Pointers
Watts	W	1 Watt	LEDs
Kilowatts	kW	1,000 Watts	Average US Households
Megawatts	MW	1,000,000 Watts	Aircraft Carriers
Gigawatts	GW	1 Billion Watts	Medium Size Cities
Terawatts	TW	1 Trillion Watts	Large Countries

Note: whether a prefix is capitalized or not can alter its meaning in some cases.

How about a Watt-hour?

A Watt-hour (Wh) is a basic unit of energy measurement. Watt-hours are used to measure how much energy is consumed by or generated by a system.

1 Watt-hour is the amount of energy that would be consumed by or generated by a system if the system operated at power level of 1 Watt for a time period of 1 hour. Note that, all of the prefixes listed above apply to Watt-hours the same way that they apply to Watts (e.g. 1 kWh = 1,000 Wh).

Energy Used	At This Scale
15 Wh	Compact Fluorescent Bulb for 1 hour
250 Wh	Xbox 360 and LCD Television for 1 hour
1 kWh	Average US Household for 1 hour
23 kWh	Nominal Rating of Electric Vehicle Battery
12 MWh	Average US Household for 1 year
20 GWh	Small US Town for 1 year
57 TWh	Total Massachusetts Electricity Consumption (2010)
3,750 TWh	Total US Electricity Consumption (2010)

Watts or Watt-hours?

Despite the similarity in name a Watt-hour is very different from a Watt!

For example, If I asked you, "How much power are the appliances in your house using right now?" Your response should be something like, "They are consuming 800 W."

Likewise, If I asked you, "How much energy do the appliances in your house use in a year?" Your response should be something like, "They normally consume about 9,000 kWh."

If you used the two units interchangeably (such as answering the first question as "800 Wh" instead of "800 W), it would be the same as confusing any other two units.

For example, if I asked you, "How fast were you driving when the cop pulled you over?" and you answered, "About 30 miles." In this case, your answer simply does not make sense!

Appliance Power

The more Watts an appliance is rated at, the more energy it consumes. You can think of this as describing how 'hungry' an appliance is. That is, how much energy does the appliance need to consume in order to do its job? In many cases, a higher power rating means an appliance can work more effectively. Of course, a higher rating does not necessarily mean that an appliance is doing a better job, sometimes it can mean a lack of efficiency. To put this in perspective, let me offer two familiar examples.

Example 1: Microwaves A 600 W microwave will typically take longer to cook your TV dinner than a 900 W microwave. In this case, the 900 W microwave is 50% more powerful than the 600 W microwave, which allows 50% more energy to be applied toward cooking your TV dinner each second that the microwave is running. In this example, the added power means the job is done more effectively. Example 2: Light bulbs A 100 W incandescent light bulb can often be replaced with a 25 W compact fluorescent light bulb and essentially the same amount of light will be provided. With each light bulb, enough light is provided to read a book each second that the light is turned on. In this example, the incandescent bulb is more powerful but less efficient, so a lot of energy is wasted by heating up the coils in the bulb.

Reading an appliance's power rating can also, sometimes, be a bit misleading. Some appliances - such as microwaves - have straight forward power ratings. (e.g. A 900 W microwave should be using 900 Watts of power when it is in use.) However, other appliances have power ratings listed that represent their maximum energy use.

Refrigerators, for example, are typically plugged in and 'turned on' all of the time, but a 720 W refrigerator is not constantly using 720 Watts of power. Instead, refrigerators may use their rated power for 5 minutes and then use no power for 25 minutes before switching back on again. In this case, a 720 W refrigerator would have a peak power consumption of 720 W and an average power consumption of 120 W (or 720 W x 5 minutes/30 minutes).

Generator Power

The more Watts a generation system is rated at, the more powerful it is. You can think of this as describing how 'strong' the generator is. That is, would energy being generated feel like a blast from a fire hose? Or, would it feel more like a squirt from a small water pistol?

Electric generator power ratings can also be a little tricky. For most types of generators (such as coal power plants, nuclear power plants, wind turbines, etc.), the so-called nameplate capacity indicates the maximum possible power generation under optimal conditions. However, solar photovoltaic (PV) generation systems can be especially confusing, because they have two nameplate capacities: an AC nameplate capacity and a DC nameplate capacity.

The AC nameplate capacity of a PV generator is relatively straightforward; it indicates the maximum AC power output that the system's inverter(s) can produce. On the other hand, the DC nameplate capacity of a PV generator indicates the expected cumulative DC power output for all of the solar PV modules under Standard Test Conditions (STC) without applying any derates, which in some cases compound to result in an actual output that is much higher than the DC nameplate capacity (see description below).

Solar PV Industry: Standard Test Conditions (STC)

In the PV industry Standard Test Conditions (STC) describe the production of a solar PV module at 25°C (77°F) at sea level with 1000 W/m² of incoming solar radiation (irradiance). While changes in atmospheric pressure can contribute minor changes in the actual output, changes in temperature and irradiance significantly alter the actual output of a solar PV module at different locations and throughout the year (and even throughout a single day). Depending on the location and time (and the amount of moisture and other particulates in the atmosphere) an array of solar PV modules may receive 100-1400 W/m² of solar irradiance during the daytime. This range includes irradiance both less than and greater than the STC irradiance. Greater irradiance will allows for a derate ratio that is greater than 1. Also, the cells in solar PV modules are better able to transfer electricity in cooler temperatures, which also allows for a derate ratio that is greater than 1. As a result, on a hot (cloudy) summer day a solar PV module will probably have  much lower output than the DC nameplate capacity. Conversely, on a cold (sunny) winter day a solar PV module is likely to have an actual output that is much higher than the DC nameplate capacity.

In any case, it is important to remember that the nameplate capacity of a generator is a nominal power rating, so it alone will not tell you how much energy a generator produces in a year. To determine a generator's annual energy production, you will need to multiply the nameplate capacity by the capacity factor and the amount of time in a year (i.e. Nameplate Capacity [W]x Capacity Factor x 8,766 hours = Energy Production [Wh]).

Other Terminology

Well, unfortunately, it would take an entire book or a semester course to explain all of the nuances of power, energy, voltage, and current related to energy generation and consumption. However, to help you along, I have put together a brief glossary of terms that are commonly used in the energy industry. I decided to put them in a logical (rather than alphabetical) order, so that you can read the glossary a bit like a book.

Glossary of Energy Industry Terminology

Nameplate Capacity	The maximum* potential power output or consumption for which a generator or appliance is rated to operate under optimal conditions (so called because this is often the nominal value listed on the name plate of the system).
Derate	A multiplier that describes what portion of a nominal system output remains intact after the effect of a non-optimal or non-standard condition is considered (often used to calculate the impact of changes in operating temperature or other environmental variables).
Capacity Factor	The Actual Power Output compared to the Nameplate Capacity over a period of time (typically as a %).
Availability Factor	The portion of time that a generator is physically able to operate (as opposed to being offline for maintenance; typically as a %).
Peak Power	The maximum amount of power that is actually generated or consumed during a defined period of time.
Average Power	The total amount of energy generated or consumed during a defined period of time divided by that amount of time.
Load Factor	The Average Power divided by the Peak Power for a defined amount of time (normally used to describe how well a utility grid is utilized; typically as a %).
Direct Current (DC)	Refers to power that is generated, consumed, or transferred at a steady voltage during normal operation (commonly used in batteries and solar photovoltaic modules).
Alternating Current (AC)	Refers to power that is generated, consumed, or transferred using a fluctuating voltage, which causes the current to alternate directions (commonly used in household appliances and long distance utility lines).
AC Voltage (VAC)	The voltage range over which AC power fluctuates (in the US, household electrical outlets nominally operate at ~120VAC, which means the actual voltage fluctuates between +120V to -120V many times per second).
Grid Voltage	Refers to the AC Voltage that must be maintained on a utility grid in order to ensure safe and reliable operation (neighborhood utility lines typically operate between a few hundred volts and several thousand volts).
Grid Frequency	Refers to frequency with which Grid Voltage fluctuates each second (in the US, household electrical outlets nominally operate at ~60Hz, which means that each second the Grid Voltage fluctuates through 60 cycles from +120V down to -120V and back up to +120V).
Inverter	A device that turns Direct Current (DC) power into Alternating Current (AC) power (a common component of solar photovoltaic generation systems).
Converter	A device that turns Alternating Current (AC) power into Direct Current (DC) power (often referred to as "AC Adapters" and are used in appliances and electronic devices that run DC power or rechargeable batteries).
Transformer	A device used to increase or decrease voltage (higher voltages are used to transport power over long distances with minimal losses; lower voltages are needed to operate common appliances).

*For solar photovoltaic modules, the Nameplate Capacity typically indicates the DC power output during standard test conditions of the module during its first year of operation.

I hope that you found this post useful. In the future, I will try to link to this post whenever I have included one of the terms listed above.

Cheers,

Sean Diamond

Massachusetts Utility Net Metering Cap

Hello Readers,

Earlier in this series, I described how utility net metering caps conflict with renewable energy installation goals. In this post, I will build upon the context established in the previous post about the Massachusetts Renewable Portfolio Standard (RPS), and I will explore the purpose of and issues with the net metering cap in Massachusetts.

To begin, let us consider the question: What is the purpose of capping net metering rules in the first place? There are two possible reasons why a net metering cap would have been introduced into the regulations: (1) there are physical safety concerns related to allowing significant percentages of net metered systems to interconnect or (2) utility companies lobbied for its introduction.

Safety Concerns with Net Metering

As I described in my graduate dissertation, the addition of a large percentage of intermittent renewable generation, such as solar and wind DG systems, has the potential to cause power quality problems on a non-smart utility grid. In other words, without sufficient demand response and/or energy storage capacity incorporated into grid, the modern utility grid infrastructure may not be able to handle large swings in power output (such as those that may be associated with changing wind speeds or clouds passing over a photovoltaic system) especially if intermittent renewable systems account for roughly 20% or more of a utility company's annual peak demand.

Even so, it is important to note that both DG-scale and large-scale (non-DG) intermittent renewable systems have the potential to cause physical stress on the utility grid infrastructure. In fact, the spikes and falls in production that can be problematic for the grid as a whole have a tendency to average-out across an aggregate of many DG systems, and therefore provide more stable grid voltages compared to a single large-scale system. Again, renewable DG systems should theoretically be favorable for the grid and provide a reason to encourage as much net metering as possible.

So, again, why put a cap on net metering? Understandably, no one wants huge swings in grid voltages to cause rolling brown-outs and damage to appliances, so perhaps a cap at 15-20% of the annual peak demand may be warranted if the grid is too 'dumb' to handle the input of renewable DG systems. However, in Massachusetts the cap has been established at 1% of annual peak demand for homeowners and businesses and at 2% of annual peak demand for municipalities and other government entities (for at total cap of 3% of annual peak demand).

National Grid's Net Metering Cap

National Grid’s historical peak load of 5,131 MWs occurred on August 2, 2006 in Massachusetts Electric territory; making the 1% limit 51.31 MWs and the 2% limit 102.62 MWs. As of July 5, 2012 in Massachusetts, there are 45,244 KWs with net-metering service under the 1% limit and 11,291 KWs with net-metering service under the 2% limit. As of July 5, 2012, there are 443,588 KWs with applications in the process of being interconnected under the 1% limit and of those 64,211 KWs have returned the Schedule Z.

Excerpt from National Grid Net Metering Website

Keeping in mind that 1,000 kW equals 1 MW, it is clear that, utility companies such as National Grid, already have more applications to interconnect net metered DG systems than they have room under their 1% private cap. This begs two questions:

• Why is there a larger set aside for public entities (i.e. a 2% cap for municipalities and other government entities) in Massachusetts?
• What is going to happen to all of the private entities that are applying to interconnect DG systems in Massachusetts?

As it turns out, the Massachusetts DPU is already arranging for the creation of a waiting list for entities attempting to interconnect DG systems after the cap limit is reached (see pdf). However, what good will this do if the net metering cap does not increase? The answer is appears to be little-to-no good at all.

Lobbying for a Net Metering Cap

Ostensibly, it is plausible that utility companies would have lobbied the state legislature on the issue in order to protect their profit margins. That is, logically, offering more net metering credits to DG system owners results in a proportionate decrease in the revenue that a utility company is able to collect, and therefore a proportionate decrease in profit margins. Thus, it would be equally logical in most cases for utility companies to lobby the legislature in support of a cap on net metering credits, thereby protecting utility company profit margins.

As I said, in most cases this would be logical, and in many states this may very well be the case. However, in Massachusetts in particular this makes very little sense due to a provision known as decoupling, which connects utility company profits with the number of customers served rather than the amount of electricity consumed.

Decoupling

The Department of Public Utilities (DPU) [...] issued an Order that will begin the process of "decoupling" rates from sales volume for all of the state's electric [...] distribution utilities, in order to encourage utilities to help their customers reduce their energy consumption and take advantage of on-site renewable energy, as required by the Green Communities Act, the comprehensive energy reform law [...] signed by Governor Deval Patrick. [E]lectric utilities will file rate plans that separate, or decouple, their sales of electricity [...] from the revenues they need to collect in order to maintain the electricity [...] distribution system they are responsible for. [...] Utilities are expected to file decoupled rate plans with the [DPU] as existing rate plans expire - for most companies, by 2012 - though companies can file sooner on a voluntary basis.

Excerpt from Mass DPU Press Release

Thanks to Massachusetts' implementation of decoupling, there is little-to-no direct financial incentive for utility companies to obstruct customers looking to take advantage of renewable DG systems. Under current regulations, utility company profits will remain the same regardless of how much electricity is consumed.

Unfortunately, I do not have the personal resources to thoroughly investigate the lobbying practices of the utility companies on this matter. However, given this understanding of decoupling, it is tough to imagine that utility companies would have invested much effort or money into lobbying in favor of a net metering cap.

Although, on a related note: in a personal, off-the-record discussion with an employee of a utility company, it was suggested that part of the reasoning behind the net metering cap may simply be a lack of qualified personnel. That is, in Massachusetts, which has only recently seen a significant private sector interest in renewable DG systems with the introduction of the Solar Carve-Out of the RPS, utility companies in Massachusetts do not have enough qualified staff to safely and responsibly handle the incoming interconnection requests in a timely manner.

A Possible Solution

To summarize, capping net metering may be providing utility companies some breathing room needed to retrain current staff and/or hire qualified staff. Likewise, it may also be providing the utility companies with an opportunity to figure out how to make the smart-grid smarter (i.e. better able to handle high percentages of intermittent renewable systems).

If either of the above justifications for a net metering cap are the case in Massachusetts, that ought to be made clear to the public and the policymakers. Also, instead of setting a single net metering cap, which provides homeowners and businesses no opportunity to make plans beyond the limits of the current cap, legislators should layout a growth schedule for the net metering cap.

This growth schedule should be clearly defined and - importantly - must lead the growth of the RPS goals by at least a year. If the net metering cap remains stagnant or does not out-pace the RPS in Massachusetts: DG installers, financiers, and potential DG system hosts will continue to be frustrated and delayed by an inability to plan ahead, which will be detrimental to everyone interested in meeting the RPS goals or holding a job in the green energy industry in Massachusetts.

Requiring the utility companies to increase the net metering cap at a pre-defined rate will offer everyone involved some project planning certainty. Also - if implemented correctly - a scheduled net metering cap increase will provide utility companies the incentive they need to safely and responsibly implement beneficial smart-grid technologies, which will improve grid efficiency and reliability regardless of the success of the RPS in Massachusetts.

Sincerely,

Sean Diamond

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Massachusetts Renewable Portfolio Standard

Hello Readers,

In an earlier post, I described how, in general, the low caps on utility net metering rules undermine the goals established in a state's Renewable Portfolio Standard (RPS). Now, I will take a look at the specific case of Massachusetts, which has an aggressive RPS program and already has utility companies running into the net metering cap.

In this post, I shall provide some background on the Massachusetts RPS. Then, in the next post, I will delve deeper into some of the reasoning behind putting a cap on net metering rules in the first place before finally discussing a possible solution to the issue.

Class I Resources

In Massachusetts, eligible Class I resources include: photovoltaics (PV); solar thermal-electric energy; wind energy; ocean thermal, wave or tidal energy; fuel cells utilizing renewable fuels; landfill gas; energy generated by certain new hydroelectric facilities, or certain incremental new energy from increased capacity or efficiency improvements at existing hydroelectric facilities; low-emission advanced biomass power conversion technologies using fuels such as wood, by-products or waste from agricultural crops, food or vegetative material, energy crops, algae, biogas, liquid biofuels; marine or hydrokinetic energy; and geothermal energy.

As described by DSIREUSA.ORG

Since 2003 Massachusetts has had an RPS, which has been increasing by 1% per year since 2008 and shall continue to increase by 1% per year without a legislated limit. By the end of 2012, the Massachusetts RPS requires that utility companies ensure at least 7% of the electricity they sell is produced by Class I resources.

Also, since 2010, the Massachusetts RPS has included a Solar Carve-Out, which specifies that a certain portion of the RPS must be met using energy produced by in-state solar photovoltaic (PV) generation systems that are 6 MW or less. Under the current legislation, the Solar Carve-Out in Massachusetts is ultimately limited to 400 MW of total installed capacity.

However, the requirement that each system must be 6 MW or less means that at least 400 MW of solar distributed generation (DG) systems (officially defined as generation systems 20 MW or less) will need to be installed over the next several years. As we discussed in the previous post, the primary means of DG installation is through net metering interconnection with the local utility company, so it is likely that the 400 MW of solar DG systems will be net metered. Furthermore, even after the Solar Carve-Out is fulfilled, solar DG systems may still be used to meet the general Class I requirement of the RPS.

1% Per Year

The Massachusetts RPS quota is mandated to continue to grow at an overall rate of 1% per year. This breaks down to roughly 580,000 MWh of additional Class I electricity generated per year.1 If the entire Class I requirement were met only through solar PV systems, roughly 482 MW of new solar PV generation capacity would need to be installed each year.2 Likewise, if the entire Class I requirement were met only through wind turbine systems, roughly 265 MW of new wind generation capacity would need to be installed each year.3

It is unlikely that any single Class I technology will fulfill the entire annual RPS increase during any particular year. Instead, each year a combination of new Class I technologies will need to be installed on a massive scale. But what does that mean? Consider some examples of renewable energy installation projects at a scale comparable to the annual increase in the RPS:

• If the Cape Wind project (420 MW) were fully operational, it would only fulfill roughly one and half years worth of the increase in the RPS requirement.
• When the entire Solar Carve-Out (400 MW) is met, it will not cover an entire year of the increase in the RPS requirement.
• The Sihwa Tidal Power Plant (254MW) is the largest wave powered generator in world, which produces 552,000 MWh per year. It is located in South Korea and is part of a tidal barrier that stretches nearly 8 miles in length across a tidal inlet creating an artificial lake.

In general, all renewable energy projects have the potential to provide a variety of benefits to system owners, those seeking domestic green energy jobs, and utility companies attempting to comply with the RPS. Of course, larger individual projects (such as the Cape Wind project and the Sihwa Tidal Power Plant) involve especially complex installation and pre-installation processes, which may involve a multitude of stakeholders and may require years of studies and permitting.

As a result, such mega-scale renewable projects can take years before they begin and can cause massive, localized environmental disruptions. On the other hand, hundreds of micro-scale DG projects (such as those mandated by the Solar Carve-Out) can be installed with relative ease, provided that they make financial sense and the regulatory hurdles do not turn into stone walls.

Unfortunately, even before the Solar Carve-Out requirement has been met, utility companies - such as National Grid - have already received enough DG interconnection applications to cause concern about their net metering cap. In this case, the net metering cap regulatory hurdle may simultaneously stonewall projects and make them less financially viable. In the next post, I will take a look at the net metering cap in Massachusetts.

Sincerely,

Sean Diamond

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Notes from the "1% Per Year" Box:

1)	Estimate based on available data from the US Energy Information Administration (EIA) Electricity Data website - spreadsheet: Retail Sales of Electricity by State by Sector by Provider (EIA-861).
2)	Estimate based on the PV Watts generation calculator, which suggests that 1 MW of solar PV capacity aligned south at a 20 degree inclination can produce about 1,202 MWh/MW per year in Boston, Massachusetts.
3)	Estimate based on information provided on the National Wind Watch website, which suggests a generation rate of 2,190 MWh/MW per year is not unreasonable given a 25% capacity factor.

Utility Net Metering Caps Undermine Renewable Energy Installation Goals

Hello Readers,

As you may know, many states have set up aggressive Renewable Portfolio Standards (abbreviated RPS, and defined below) in an effort to promote clean energy job creation, foster the development of fledgling domestic energy industries, and address pollution and climate change issues. Even though policies vary widely (see map), only 12 states do not have any RPS.  Furthermore, in almost every state that has an RPS, the end-goal of the policy is to ensure that 10-33% of electricity is being generated by renewable sources within the next 5 to 15 years.

Renewables Portfolio Standards (RPS)

Renewable portfolio standards (RPSs) require utilities to use renewable energy or renewable energy credits (RECs) to account for a certain percentage of their retail electricity sales -- or a certain amount of generating capacity -- according to a specified schedule.

As defined by DSIREUSA.ORG

That is to say that: 38 states (and Washington DC) have laws mandating that by the year 2025 at the latest, 10% or more of the electricity consumed in the state must be generated from renewable energy sources (commonly solar, wind, and/or biomass). However, in many cases there are very low caps put on the state regulations that require utility companies to offer net metering to customers.

Net Metering Rules

The definition of 'net metering' varies from state to state, but in the narrowest definitions it at least allows for the owner of a distributed generation (DG) system to be credited or compensated on a 1:1 basis for electricity sent back to the utility grid (as opposed being used on-site). The credits or compensation are then applied to a customer's account to negate other electricity usage. In most definitions, credits may be saved and applied over the course of a 12 month period. In broader definitions, net metering can involve crediting multiple billing accounts for one customer and/or multiple billing accounts for multiple customers, which may or may not be limited to a specific geographic area.

In a very real sense, when electricity is generated, it is used up by the nearest possible consumer. That is to say that, the energized electrons do not care who is paying for the electricity, they just want to get rid of their energy as soon as possible. To understand the impact of this physical reality, let us consider an example, wherein your neighbor has a solar distributed generation (DG) system on their roof and they are not using up all of the energy it is producing during any particular second.

In this example, it is likely that the appliances in your house are running off of your neighbor’s solar DG system rather than the coal power plant on the other side of town. Furthermore, the utility company is benefitting from your neighbor’s solar DG system, because the coal plant does not have to run as hard (using less fuel) and because the power lines running across town are under less stress (requiring less maintenance in the long term). However, during the times when your neighbor’s system is producing less than they are using, your neighbor is drawing electricity from the other sources on the grid just like everyone else.

To ensure that utility companies are fairly compensating DG system owners for the benefits they provide, basic net metering regulations typically require that a kWh of electricity sent back onto the grid from a DG owner negate the financial burden of a kWh equivalently being consumed by the same DG owner.

Unfortunately, not every property is ideally suited for installing solar and wind DG systems, so for many businesses and homeowners it is less financially viable to install a DG system to cover their own energy needs on-site. However, many other properties are perfectly capable of supporting a renewable DG system that can produce more energy than is used on-site. As a result, property owners (and/or electricity users) often prefer to come together to co-finance larger projects on more suitable properties and share the resulting electricity, allowing for a quicker return on investment (i.e. lower electricity costs for participants). Also banks and other financial institutions are often more willing to provide up-front financing when the financial payback (and the related risk of default) is spread over many participants. But how can electricity be shared?

Because of the nature of electricity (as described above), it is often impractical for multiple businesses or homeowners to physically transfer the electricity produced by a shared DG system over long distances. Even in cases where it is feasible to physically transfer the electricity, running the necessary wires would typically create a redundant set of equipment in parallel with the existing utility lines. Instead, arrangements can easily be made to virtually connect the utility billing accounts of the physical host of the DG system and the other participants or co-owners. This is a common form of net metering.

Unfortunately, the net metering rules are often capped at a threshold equal to a very small percentage of the utility's annual peak energy demand. This means that once the total installed capacity of distributed generation systems reaches the cap, no more DG system owners are able to take advantage of the financial benefit of net metering rules (or in some cases even legally interconnect DG systems), which fundamentally limits the ability of businesses and homeowners to afford or finance the installation of new DG systems. But why is net metering important with regard to utility companies meeting their RPS targets?

Superficially, the cap on DG systems does not directly interfere with the ability of utility companies to meet their RPS targets. In fact in most cases, it is entirely possible for utility companies to finance and maintain their own commercial-scale (non-DG) renewable generation systems; however, this would require utility companies to purchase or lease large tracts of land and roof-space and hire workers to develop, construct, and maintain the equipment.

Thus, as a general practice, most utility companies have not been installing and maintaining their own renewable energy generation facilities. Instead, they rely on the purchase of RECs and SRECs from businesses, homeowners, and independent developers who finance, construct, and maintain renewable DG systems on their own property. In turn, the wide of adoption of renewable DG systems, which is hindered by restrictive net metering caps, is the de facto means of meeting RPS targets.

Rather than considering the restrictiveness of these caps on net metering in the abstract only, in the rest of this Net Metering series, I shall consider the specific example of Massachusetts, a state that has recently been gaining a lot of attention from the solar and wind industries.

Sincerely,

Sean Diamond

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Getting Rid of Fossil Fuels

Hello Readers,

Here is a video synopsis of a recent study about the climate change benefits of different energy production alternatives to coal-powered electricity grids.



You can find more information on the Carnegie Institution for Science website or view the full journal article by following the link below.

Myhrvold, N.P., and K. Caldeira, 2012. Greenhouse gases, climate change, and the transition from coal to low-carbon electricity. Environmental Research Letters, Vol. 7, 014019 doi:10.1088/1748-9326/7/1/014019. 2012.

Nerd-ly,

Sean Diamond

Energy Future TED Talk

Hello Readers,

This is potentially the most important and informative TED Talk you will see this decade. The speaker is the head of the Rocky Mountain Institute.

Please watch this.

Thanks,

Sean

Natural Gas TED Talk

Hello Readers,

I encourage you to check out T. Boone Pickens' TED Talk on conversion to natural gas. He offers some excellent facts, talking points, and arguments for the use of natural gas (at least as a bridge fuel... and possibly more).




Of course, he does not mention energy storage technology as a solution to intermittent renewable energy, but you can read more about energy storage in my dissertation.

Enjoy,

Sean

Movie Review: A Crude Awakening

Hello Readers,

Earlier this week, I watched A Crude Awakening: The Oil Crash movie directed by Basil Gelpke and Raymond McCormack. This movie, which was released in 2006 (the middle of the Bush administration), is as much a horror movie as it is a documentary.

Through a series of intertwining interviews, which are scored with a background soundtrack that would not be out of place in a slasher movie or an episode of the X-Files (similar to the background track of the trailer below), A Crude Awakening offers a prophecy of the collapse of the modern oil-based society.



A Crude Awakening is a mixed bag for environmentalists. It will both inform and frighten the audience. I did not notice statements (opinions aside) that are overtly factually incorrect; however, the tone of the movie overpowers the information. It may be good as a factual refresher for seasoned environmentalists, but I would not recommend this movie as a way to start a discussion on peak oil.

While the movie describes in detail the implications and likelihood of peak oil, it offers no sense of purpose or motivation to solve the issue. In fact, any solutions that may have been mentioned will be lost in the mosh-pit of despair that is A Crude Awakening.

The tagline of the movie says it all: "We're running out [of oil], and we don't have a plan." If you do show this movie, I would definitely follow up with a debriefing session or by handing out business cards of therapists.

Best of Luck,

Sean Diamond

Alberta Tar Sands - pipeline decision

Hello Readers,

Yesterday, I came across post about Obama's current predicament about the XL Keystone Pipeline proposal. I recommend checking out the post as it offers many links to resources and provides a review of the considerations that the president must take.

Also, you can check out the author's interview about the topic below:




...it's a bit dry, but its fairly thorough.

Enjoy,

Sean

Change... in which I can (finally) believe

Hello Readers,

As you have likely heard already, White House officials recently announced plans to install solar PV and solar hot water systems on the roof of 1600 Pennsylvania Ave. This will replace the system that was removed in 1986 during the Reagan administration. You will note that the 24-year gap roughly equals the 20-25 year warranty offered on solar panels, which means that the entire lifetime of a system could have been generating power if they had not been removed.

Although, a new solar energy system on the White House seemed like a bit of greenwashing, which would not have been surprising given the relative inaction (or at least lack of concrete action) on climate change and energy independence since Obama was elected nearly 2 years ago. However, an announcement today by Ken Salazar showed some substantial change (believe it or not).

It turns out that the White House has cleared the way for a 709 MW and a 45 MW system to be built on federal lands in California (with a few thousand more MW of capacity in the pipeline for approval by the end of the year). Granted, some may consider this a stunt for the midterm election. Even so, any election year stunt that allows for over half a million homes (and possibly closer to 2 million homes) to be powered by solar power is okay by me!

The New York Times article relating to the announcement mentioned a need for additional transmission capacity to be built. However, it did not mention any plans for energy storage! After doing all of the research for my dissertation, I cannot help but wonder if anyone in the political realm has considered that option as a way to alleviate the grid congestion that will occur when these mammoth solar generators come online.

Hopefully, the utility regulators in California, which are well aware of their options based on what I saw during the PJM-EPRI conference on Energy Storage, have the sway to make a suggestion about incorporating energy storage into these plans (and/or the budget to do it themselves!).

anti-schadenfreudlich,
Sean Diamond

P.S. Later this month I should be receiving the results of my dissertation, so I will be dispersing the final version of it accordingly. Thanks for waiting so long!

Renewable vs. Nuclear or Renewable plus Nuclear

Hello Readers,

For years now, I've been reading articles, blog posts, and op-ed pieces debating the merits of nuclear and renewable technologies and the use of them in the development of a low-carbon energy grid. Without feeling a need to reference any specific examples, both sides of the debate (which are both arguably environmentalist in nature) seem to universally agree that fossil-fuel power plants are 'evil'; however, neither side can agree on the best alternative.

Both sides of the argument tend to be concerned about the environment in some capacity and agree that reducing carbon emissions and other pollutants is a good idea. Renewable energy proponents (nuclear opponents) tend to disapprove of the radioactive waste and international security issues associated with nuclear. Whereas, nuclear proponents (renewable energy opponents) tend to site the disruption of the landscape/habitats caused by covering vast areas of land (or waterways) with solar or wind (or hydro) technologies. Meanwhile, fossil-fuel proponents (the champions of the status quo) will point to the weaknesses in either argument and completely deny climate change issues to ensure that their investments (either capital or lifestyle investments) are safe.

As a physicist in undergrad (with a basic understanding of radiation and nuclear technologies) and a climate change scientist in postgrad, I have never fully settled on either side of the renewable vs. nuclear debate. I have come to acknowledge nuclear power plants -if run responsibly- can be a relatively clean source of power. However, careful geopolitical considerations should be accounted for in the development of any new nuclear power plant (i.e. While I understand the reasoning behind sanctioning Iran, it is hypocritical of the USA to discourage other countries from developing nuclear facilities while simultaneously attempting to reinvigorate its domestic nuclear industry.). On the other hand, massive deployments of renewable generators (on the scale necessary to power even half of the current US demand) will require the disruption of not-insignificant portions of natural landscapes and will require huge infrastructural projects on the electric grids (i.e. the incorporation of energy storage and/or reinforced transmission lines).

Of course, either case -if implemented and managed responsibly- will only have a marginal environmental impact compared to the current reliance on fossil-fuels. So it begs the question: how can the renewable vs. nuclear debate turn into what it should be a fossil-fuel vs. non-fossil-fuel debate?

While reading an article about the impacts of climate change on nuclear power plants, a thought occurred to me. Why not attempt to combine the two technologies? Specifically, the article referenced the weakness of many nuclear power plants is the need to use adjacent rivers for cooling. However, this means that the heated water cannot exceed 90 degrees F, which is generally not an issue except on especially hot days (such as those experienced in the USA this past summer). Otherwise, the expelled water would start cooking the wildlife in the river.

Thus, my thought was all new nuclear plants should be coupled with concentrated solar power (CSP) plants to maximize efficiency. The CSP plant, which would need to operate at temperatures of several hundred degrees Fahrenheit, could use the expelled cooling water from the nuclear plant as a preheater. This would simultaneously allow CSP plants to produce more energy with fewer/smaller collectors and allow for more significant levels of cooling for the nuclear plant on hot days. Also, This will allow for more energy to be created for every gallon of water used (e.g. up to 800 gal/MWh for CSP), and in a worst case scenario the CSP mirrors could be turned away from the sun to allow the system to act as a massive radiator for the attached nuclear plant.

Such a solution may not fully alleviate the concerns of either side of the renewable vs. nuclear debate, but it may help to bring the how to 'solve' climate change debate back into perspective. Ultimately, as both sides of the debate continue to batter each others' weaknesses rather than search for solutions, a stalemate only supports the status quo.

Thanks for reading! Please leave your comments or objections down below.

Sean Diamond

Wind Turbine Intermittency

Hello Reader,

I wanted to draw your attention to a New York Times article from the past week that highlights one of the major challenges facing developed countries as we try to connect increasing numbers of wind turbines to national and regional electricity grids. That is: intermittency.

Wind turbines are notorious for generating intermittent energy. From a physical perspective this makes sense, because wind does not blow at the same speed all the time. However, when it comes to the electricity grid intermittency can be a huge issue.

On a very small scale, such as a single isolated wind turbine on a farm, this issue can be over come by simply combining the wind turbine with a battery storage system. In such cases, intermittency is not really an issue unless the wind simply stops blowing for days at a time.

On a somewhat larger scale, such as the current state of the US electricity grid, where wind turbines only make up a small percentage of electricity generation the fluctuations are manageable. That is the gaps in generation caused by wind turbine intermittency can be filled in by other generation sources.

Of course, as the article indicates when wind energy starts to make up larger percentages (e.g. 20%) of generation sources, intermittency can pose serious risks to grid stability (e.g. increasing the risk of brownouts and blackouts). The article suggests studies are testing the possibility of connecting multiple turbine farms together to level off the effects of intermittency and provide a more consistent power source. From a physical perspective this also makes sense because when the wind is blowing in one location it may not be blowing in another and vice versa. This means electricity generation will be averaged out.

While this does appear to be a crucial step towards large scale implementation of wind energy, more infrastructural concerns must be addressed. One such step includes the mass introduction of electrical energy storage, which allows electricity to be produced at one point in time (e.g. when the wind is blowing hardest) and used at another point in time (e.g. when you wake up and turn on your electric razor). Unfortunately, the current structure of the electricity grid is not compatible with this concept. As it stands, electricity must be produced as it is being used and at no other time.

Not only is this an issue for installing wind turbines, but it also has massive impacts on the efficiency of traditional fossil fuel and nuclear plants as well. As such, energy storage is the topic of my postgraduate dissertation. Next week I will post part of my dissertation proposal, which explains more about the issue and the need for research into the field. In the meantime, I encourage you to look into the topic for yourself.

The article I referenced within this post is:
A Grid of Wind Turbines to Pick Up the Slack
By HENRY FOUNTAIN
Published: April 12, 2010
http://www.nytimes.com/2010/04/13/science/13obwind.html

Sincerely,

Sean Diamond

Wind vs. Nuclear Power

Dear Reader,

To divert from the usual flow of assignments, I am posting a response to a discussion on Linked-In in which I have recently taken part. The original post mentioned in the writing below refers to a CNN article entitled "Nuclear renaissance -- not dead yet" that can be found on cnnmoney.com. Please enjoy...

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Mr. Whealan,

To return to the topic at hand, I would like to consider the rent issue that you raised initially. In particular, let’s use the figures available in the article indicated in the original post. According to the article, the nuclear power plants in question would cost $10 billion ($10,000,000,000) to construct and would have a capacity of 5400 MW. If we consider that newly constructed nuclear facilities have regulated lifetimes before they need to be decommissioned for safety purposes, we can guess at a ‘rent’ for a nuclear facility. To keep the number simple, I will assume that the new facilities will have a lifetime of 50 year. Therefore, the ‘rent’ can be considered ($10,000,000,000 / 50 years =) $200,000,000 per year.

I realize that economist would argue that the money would be significantly reduced in value by the end of the 50 lifetime of the system due to discounting. However, given the assumption that the initial payment is made in the form of a loan (of some form or another) that will need to be paid with interest by someone (either tax payers in the case of subsidies or rate payers in the case of consumers) it seems reasonable enough to use the $200,000,000 per year figure, so let’s stick with that.

Now, we need to figure out the equivalent ‘rent’ for 5400 MW of wind-generated capacity. While I do not know what the size of the turbines you are referencing is, I will assume that we can use 2 MW turbines (to keep the math simple). This means that we will need (5400 MW / 2 MW =) 2700 wind turbines. Using your suggested rate of $10,000 per acre, and using an assumption of 1 turbine per acre, the cost of rent would be ($10,000 * 2700 =) $27,000,000 per year.

To be fair, we need to also include the construction/installation costs as we did in the nuclear case. According to windustry.org (http://www.windustry.org/how-much-do-wind-turbines-cost), an installed 2 MW wind turbine will likely cost about $3.5 million ($3,500,000). So our installation costs would be ($3,500,000 * 2700=) $9,450,000,000 in total. Or using a relatively short lifetime of 20 years, the installation portion of the rent would be about $472,500,000 per year. This means that the total ‘rent’ would be just under $500,000,000 per year.

Thus on the face of the issue, the wind turbine system would cost 2.5 times more per year. However, this disregards maintenance costs, fuel costs (and all cost associated with procuring fuel … none for wind, and substantial costs for nuclear), and decommissioning costs (and all costs associated with disposal … which I believe would actually be negative for wind since most if not all materials could be recycled, and which I believe would be very significant for nuclear if you consider that appropriate technologies for disposal or long-term storage have not really been developed and tested yet).

Thus, in my personal opinion, I believe that it is favorable to implement wind technologies where it is a possibility in place of nuclear technologies. Unfortunately, wind turbines suffer where nuclear power has an advantage in the phrase “out of sight, out of mind” on two levels. The first is that as you point out, wind turbines tend to be very visible, whereas nuclear power stations are much more compact. The second is that the users of the energy must suffer the environmental and financial drawbacks as they use them in the case of wind turbines, or the users may divert them for several generations in the case nuclear power.

In closing, thank you for prompting me to critically analyze the situation rather than simply go with what others have heard. I will be posting some form of this reply on a blog that I have had to create for a sustainable consumption course that I am currently taking. I hope that this has given you something to consider that you find digestible and not elitist. Also, if you find any trouble with my math or assumptions, please let me know.

Sincerely,

Sean Diamond